What are Twitter API limits?

If I want to use Twitter API for following/unfollowing then what are the limits? How many people per hour/day can I follow? Also, what is the deal with proxies? If I create my own "app" and get the api key then will Twitter give a sh*t if I use 10 accounts from the same IP through the same API key? Will the API limits be per account or per all total usage?

Thanks!

no more follows than 250 a day for new accounts

If i am not mistaken you can go to the twitter developers page and it will tell you the comment/like/follow limits for your app in sandbox mode and live mode.